A new Barremian bivalve assemblage from La Tosca Member of the Huitrín Formation, Neuquén Basin, Argentina

LAZO, D.; DAMBORENEA, S.E.

Plymouth, Gran Bretaña

Simposio; 8th International Symposium on the Cretaceous System; 2009

University of Plymouth

The Huitrín Formation comprises marginal marine sediments of 300 m of maximum thickness that were deposited during Barremian to Early Aptian times. It is divided into three units: Troncoso, La Tosca and Salina Members. In particular, the La Tosca Member is composed of a monotonous succession of pale carbonates of 50 m of maximum thickness alternating with subordinated shales deposited during the final connection stages of the Neuquén Basin to the Pacific Ocean. These carbonates are interpreted as deposited in a variety of settings including proximal tidal flats connected to protected shallow lagoonal facies and proximal to distal high and low energy ramp facies. The fossil record has been poorly studied even though it is highly abundant at different locations. Most previous geological studies only mentioned the presence of bivalves, gastropods and serpulids without figured specimens. The main purpose of the present contribution is to give a taxonomic update of the bivalve assemblage recorded, based on newly collected specimens.